The cost of replacing a furnace varies greatly ... This is risky work, with the risk of gas leaks high if you make even the smallest of mistakes or fail to connect something up correctly.

Oil, natural gas, and propane can be more costly,” Graham concurs. If you only replace the furnace, the cost is lower.

The expense of maintaining and upgrading the electric grid is also driving up costs. Natural gas prices are also higher. "A family using natural gas to heat their home will spend about $644.